In a solid-state imaging device of a complementary metal oxide semiconductor (CMOS) type, a flicker like a lateral strip occurs under a fluorescent lamp. As a measure against the flicker, there is a method of adjusting a gain of a signal level of each of lines through signal processing (Japanese Patent Application Laid-Open No. 2003-319204 and Japanese Patent Application Laid-Open No. 2004-222228). As another measure against the flicker, there is a method of switching accumulation time in a unit of a half of a power supply frequency of the fluorescent lamp to prevent the occurrence of the flicker and, when a light amount is in the middle of a light amount of the fluorescent lamp, adjusting a digital gain to supplement a signal amount (Japanese Patent Application Laid-Open No 2003-18458). As a method of suppressing the flicker without reducing the signal amount, there is a method of controlling accumulation time in line units (Japanese Patent Application Laid-Open No. 2007-215062).
However, in the methods disclosed in Japanese Patent Application Laid-Open No. 2003-319204 and Japanese Patent Application Laid-Open No. 2004-222228, a frequency of the flicker cannot be detected, scanning time for a plurality of fields is required for detection of the flicker, and the flicker like the lateral stripe fixed at the time of 60 hertz cannot be suppressed. In the method disclosed in Japanese Patent Application Laid-Open No. 2003-18458, the signal amount is as small as a half at the minimum and a signal to noise ratio is deteriorated by about 3 decibels by shot noise. In the method disclosed in Japanese Patent Application Laid-Open No. 2007-215062, because the flicker is detected from a change in a light amount during imaging under the fluorescent lamp illumination, if a subject has light and shade, the flicker cannot be accurately detected.